Searching for Metallic Frost on Venus
Planetary Sciences doctoral student Sara Port is using computer modeling at Japan’s Okayama University this summer to further her research into “metallic frost” on Venus. Here is her dispatch from the field:
Data collected on Venus from NASA and the USSR orbiters back in the 1970s-1990s detected unusual radar reflecting surfaces on the tops of its mountains. There are several theories on what could cause such a signal, but there is a consensus among the community that it is due to some metallic material, though we have yet to determine the composition. Due to its appearance in high altitude locations it has since been dubbed “metallic frost.”
There are two parts to my research project. The first is to observe how the temperature in the atmosphere of Venus would change if we altered the concentration of the atmospheric components. This will inform us on the stability of Venus’ atmosphere and if it has varied in the past in both temperature and composition. The second part is to model the interaction between the atmosphere and the surface minerals, while taking into consideration the temperature changes modeled in part one.
A strong background in modeling is essential for planetary scientists, since direct access to these planets is beyond our reach and because missions are so rare. These models will help us better understand Venus, as well as the formation of metal frost.
To conduct this research, I have a Venus simulation chamber here at the Arkansas Center for Space and Planetary Sciences that replicates the temperatures, pressures, and atmospheric composition on Venus. I study the interaction between possible metal frost candidates, such as pyrite, pyrrhotite, and bismuth/tellurium/sulfur mixtures, as well as gases found on Venus, such as CO2 (carbon dioxide), SO2 (sulphur dioxide), and COS (carbonyl sulfide) at Venusian temperatures and pressures. My goal is produce a mineral in my chamber that is stable in the cooler, highland conditions and not stable in the hotter, lowland conditions, just like metal frost.
However, the chamber is small and cannot take into account many other factors that exist on a planet, such as climate. Therefore, I wanted to work with George Hashimoto at Okayama University in Japan to help model some of these situations. Under his tutelage, I’m working with a computer code to observe if Venus has undergone a recent climate change (part 1) that could explain the origin of the metal frost (part 2). The code was originally created for Earth, but has since been modified to include Venus data taken from previous Venus orbiters and landers.
I’m interested in Venus because I’ve always loved planets. I remember that I once corrected my kindergarten teacher when she stated that Jupiter only had four moons (I believe at the time there were around 50 moons).
When I came to the U of A, my adviser had a research project on Venus, and I immediately jumped on the opportunity. I think Venus is fascinating because it’s considered Earth’s twin sister due to their many similarities, yet they are exceptionally different. Venus’ surface temperature is 860° F with a crushing 95 bars of pressure (Earth is 1 bar). Venus’ atmosphere is also composed of 97% CO2 atmosphere and has sulfuric acid droplets in the atmosphere.
I think we can learn great deal about Earth and planetary formation by having a better understanding about Venus’ origins. Unfortunately, Venus is not a very popular planet to send probes and orbiters to due to its hellish surface conditions.
About Okayama University:
Okayama is an intermediate sized city towards the western end of Japan. The campus that I am going to is perhaps the same size as the U of A. It was founded in 1870 and is ranked in the top 13 global universities in Japan. The University of Okayama has a strong emphasis on science and engineering.
Port’s study in Japan was made possible by a National Science Foundation East Asia and Pacific Summer Institutes internship and a Sturgis International Fellowship. Her research at the U of A is supported by a Doctoral Academy Fellowship, a Zonta International Amelia Earhart Fellowship and a NASA Solar System Workings grant.